package com.lc.nlp4han.ml.model;

/** Object which compresses events in memory and performs feature selection.
 */
public interface DataIndexer {
  /**
   * Returns the array of predicates seen in each event.
   * @return a 2-D array whose first dimension is the event index and array this refers to contains
   * the contexts for that event.
   */
  public int[][] getContexts();

  /**
   * Returns an array indicating the number of times a particular event was seen.
   * @return an array indexed by the event index indicating the number of times a particular event was seen.
   */
  public int[] getNumTimesEventsSeen();

  /**
   * Returns an array indicating the outcome index for each event.
   * @return an array indicating the outcome index for each event.
   */
  public int[] getOutcomeList();

  /**
   * Returns an array of predicate/context names.
   * @return an array of predicate/context names indexed by context index.  These indices are the
   * value of the array returned by <code>getContexts</code>.
   */
  public String[] getPredLabels();

  /**
   * Returns an array of the count of each predicate in the events.
   * @return an array of the count of each predicate in the events.
   */
  public int[] getPredCounts();

  /**
    * Returns an array of outcome names.
    * @return an array of outcome names indexed by outcome index.
    */
  public String[] getOutcomeLabels();

  /**
   * Returns the values associated with each event context or null if integer values are to be used.
   * @return the values associated with each event context.
   */
  public float[][] getValues();

  /**
   * Returns the number of total events indexed.
   * @return The number of total events indexed.
   */
  public int getNumEvents();
}